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Shenoy" References: <20260312044434.1974-1-kprateek.nayak@amd.com> <20260312044434.1974-8-kprateek.nayak@amd.com> <5b1228b7-5949-4a45-9f62-e8ce936de694@arm.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <5b1228b7-5949-4a45-9f62-e8ce936de694@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Received-SPF: None (SATLEXMB04.amd.com: kprateek.nayak@amd.com does not designate permitted sender hosts) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH2PEPF00000099:EE_|CH8PR12MB9766:EE_ X-MS-Office365-Filtering-Correlation-Id: 68cb2b74-0001-4950-8f86-08de830aee66 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|36860700016|82310400026|376014|7416014|56012099003|18002099003|22082099003|7053199007; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(1800799024)(36860700016)(82310400026)(376014)(7416014)(56012099003)(18002099003)(22082099003)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 7b1pfyq/dSIqansPYuL6oze/7RXWxviF5Wxi0XKBzeiJtW+iUll4MVQwAg8s7jKKtBL+mDApzuWFFCKOBY6/4mTCgXWjJI/eZIes67fsMi/q9XxUKkqJAxLXcV3trOkzL+/NSJYdOpNyA0a9JByD1nN23XdAJEs6tcnqfsQ1paAOb5dljniayUZh7fHiIU6zPndT8Pk45hAGHpU8bZV6ggjX1bNI6UW0UwoC9ivcCyiAkk6kto/zrEHlogCNlqgyaKJdEWxzN81mtugODujO73brwo6WnqOl4v6Ya57NXD7yy1XWxhIbPkoMEsPmIv8syr7ww5L3pfkguARek9FBoKma8829Txmr9IW5j6yN0A26Aia7zvfAFn4hPRyZYbbXCFCxzxe9Bt52Mcn2YM66uK/WXU9udweMvlXCODlIcGdqdw1MQKA0ymQLpUV8atAd X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Mar 2026 03:20:10.5220 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 68cb2b74-0001-4950-8f86-08de830aee66 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CH2PEPF00000099.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH8PR12MB9766 Hello Dietmar, On 3/16/2026 5:06 AM, Dietmar Eggemann wrote: > We need to adapt em_cpu_energy() in include/linux/energy_model.h as > well. I clearly didn't test the EAS bits! I'll make sure to spin something up with QEMU next time to hit these paths. > > ---8<--- > > From 74f9067751b02f4bd0934ba6d47f2a204c763abe Mon Sep 17 00:00:00 2001 > From: Dietmar Eggemann > Date: Sun, 15 Mar 2026 23:45:39 +0100 > Subject: [PATCH] PM: EM: Switch to rcu_dereference_all() in wakeup path > > em_cpu_energy() is part of the EAS (Fair) task wakeup path. Now that > rcu_read_{,un}lock() have been removed from find_energy_efficient_cpu() > switch to rcu_dereference_all() and check for rcu_read_lock_any_held() > in em_cpu_energy() as well. > In EAS (Fair) task wakeup path is a preempt/IRQ disabled region, so > rcu_read_{,un}lock() can be removed. > > Signed-off-by: Dietmar Eggemann Thank you for catching my mistake and for the fix! Feel free to include: Reviewed-by: K Prateek Nayak > --- > include/linux/energy_model.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h > index e7497f804644..c909a8ba22e8 100644 > --- a/include/linux/energy_model.h > +++ b/include/linux/energy_model.h > @@ -248,7 +248,7 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, > struct em_perf_state *ps; > int i; > > - WARN_ONCE(!rcu_read_lock_held(), "EM: rcu read lock needed\n"); > + lockdep_assert(rcu_read_lock_any_held()); > > if (!sum_util) > return 0; > @@ -267,7 +267,7 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, > * Find the lowest performance state of the Energy Model above the > * requested performance. > */ > - em_table = rcu_dereference(pd->em_table); > + em_table = rcu_dereference_all(pd->em_table); > i = em_pd_get_efficient_state(em_table->state, pd, max_util); > ps = &em_table->state[i]; > -- Thanks and Regards, Prateek